Within our organisation we have our own SBS server using Exchange 2013 and Optus as our providor. We are having email delivery failures with a Non-Delivery message showing the following information (names have been changed for obvious reasons) when sending some emails :
Delivery has failed to these recipients or groups: email@example.com Your message wasn't delivered because the recipient's e-mail provider rejected it.
The following organization rejected your message: mail105.syd.optusnet.com.au.
Diagnostic information for administrators:
Generating server: OOO-SBS.ooo.local
mail105.syd.optusnet.com.au #551 5.7.6 Message rejected as spam (CM). ##
Original message headers:
Received: from OOO-SBS.ooo.local ([fe80::a831:be7f:cb5f:7170]) by
OOO-SBS.ooo.local ([fe80::a831:be7f:cb5f:7170%17]) with mapi id
14.03.0319.002; Thu, 16 Mar 2017 07:11:58 +1000
From: Person To: Other Person Subject: FW: Optus Account xxxx xxxx xxxx xx is ready for viewing and payment
Thread-Topic: Optus Account xxxx xxxx xxxx xx is ready for viewing and payment
Date: Wed, 15 Mar 2017 21:11:58 +0000
Accept-Language: en-AU, en-US
Solved! Solved: Go to Solution.
Just had a quick check of that Optus mail server on the link below and it appears on several blacklists. If you send an email to any person using those blacklists your mail will bounce. Best to have a word with support and see if they can fix the problem or try a different mail server in the interim if that is possible.